This invention relates to methods of casting metal in bonded sand grain, gas-permeable, shell molds, for example, those described in Chandley et al. U.S. Pat. No. 4,340,108, which is hereby incorporated by reference, and to apparatus used for such casting methods.
As more fully described in Chandley et al., in such a casting method, the top half of a gas-permeable shell mold may be secured to the opening of a hollow support cylinder whose inner chamber is connected to a vacuum pump. In this way, the vacuum in the cylinder chamber draws molten metal into the mold cavity from a reservoir in which the bottom of the mold has been submerged.
It is desirable that the means for attaching and separating the mold to the cylinder be quick, simple, and reliably repeated in a mass-production procedure.
To attach the mold to the cylinder opening during the casting process, Chandley discloses a pair of spring clips, extending upwardly along the outside of the upper side surfaces of the mold; these clips support the mold against the cylinder in position so that the sealing surfaces of the mold abut sealing surfaces of the cylinder. The clips are made of a metal that is destroyed at casting temperatures, thus freeing the mold to be removed when the vacuum is released.